It's such a high number that it would took months to process. The video case study demonstrates how machine learning can help the overall user experience of a popular product.
The most interesting part of the video is at 1:50 where you can hear and see how AI can help designers and developers to process this enormous quantity of data. For both AirBnB hosts and guests (and of course for AirBnB itself) the main goal is to see an image gallery with the most appealing living room images first.
If you think about it, AirBnB's whole business model depends on premium quality images – it’s a kind of a photographer’s portfolio.